Oil Agglomeration Research Articles

No.5 油凝集選炭法におけるpH 調製の選炭効率及び脱硫率への影響(改質・処理・クリーン化(2),その他)

No.5 油凝集選炭法におけるpH 調製の選炭効率及び脱硫率への影響(改質・処理・クリーン化(2),その他)

Recovering molybdenite from ultrafine waste tailings by oil agglomerate flotation

Neutral oils like kerosene, diesel, transformer and rapeseed oil were used as collectors or bridging reagents in conventional flotation and oil agglomeration flotation (OAF) process, and a promising OAF process has been developed for the recycling of ultrafine molybdenite resources from the waste tailings. The average size of collected particles (d50p), agglomerates (d50a) and their distribution of the froth concentrate were determined by laser particle size analyzer or sieve analysis. Conventional flotation froth cannot catch the ultrafine particles, so it is an ineffective process to recover molybdenum metal in the waste tailings, while OAF has some advantages to recover fine minerals. And the best result was obtained from transformer oil due to its appropriate length of carbon chain, kinematic viscosity and cyclical structure. The oil amount plays a very important role on average size of the particles, with the increase of transformer oil from 2.0 to 13.8kg/t, d50a increases from 0.15 to 0.68mm and d50p decreases from 9.06 to 2.05μm. This finding suggests the bigger the d50a, the smaller the d50p, and the higher the recovery of molybdenite.The appropriate conditions for recovering ultrafine molybdenite were determined as follows: dosage of frother: 0.5kg/t, natural pH: 6.2, stirring time: 3 min, and stirring intensity:400–600r/min. Lastly, the closed cycle test and industrial application in the producing scale of 500t/d were carried out, and result shows 95% molybdenum was recovered with a satisfied grade of 22.62%.

Converting coal slurry to concentrate for coke production

After technical analysis, coal slurry is enriched by oil agglomeration. The suitability of the resulting concentrate for use in coke production is analyzed.

1-1-1 油凝集選炭法における石炭種の影響因子の調査(1-1 選炭、微量元素、燃料電池,Session 1 石炭・重質油等)

1-1-1 油凝集選炭法における石炭種の影響因子の調査(1-1 選炭、微量元素、燃料電池,Session 1 石炭・重質油等)

The Selective Oil Agglomeration of Combustibles in Fines of Low Grade Lignite of Barmer Rajasthan (India)

Oil agglomeration is one of the more effective methods for recovering and reducing ash of lignite fines. The effects of some parameters that markedly influence the effectiveness of selective oil agglomeration, such as solid concentration, amount of agglomeration oil, agglomeration time, and effect of various hydrocarbon oils were systematically studied. The sample of Giral Lignite Mines of RSSM in Barmer district was agglomerated with different hydrocarbon oils, such as toluene, diesel, and pine oil. The calorific value of the lignite sample has been recovered to 2,190 kcal/kg from 1,687 kcal/kg and reduced ash from 35.50 to 28.47%.

Influence of Hydrophobicity on Agglomeration of Dolomite in Cationic-Anionic Surfactant System

In this study the modified procedure of the oil agglomeration process was carried out, where the emulsion of dodecylammonium hydrochloride (DDAHCl) solution and kerosene was added to the mineral suspension. The aim of this work was to research the oil agglomeration of dolomite mineral by the contact angle, zeta potential and surface free energy measurements. The relationship between the investigated parameters and the oil agglomeration as well as shear flocculation was revealed. The mechanism of oil agglomeration of hydrophilic particles in cationic-anionic surfactant system has been proposed. It was concluded that oil droplets interact rather with aggregates of particles modified by anionic surfactant than the single mineral particles as was explained for naturally hydrophobic particles.

Investigation of optimum conditions in coal–oil agglomeration using Taguchi experimental design

The present study was undertaken to optimize the oil agglomeration process parameters for maximum recovery of coal fines using analysis of mean (ANOM) statistical approach based on the Taguchi parameter design methodology. The various operational parameters considered during the current study were the type of coal, type of oil, coal particle size and pulp density. The study reported a maximum recovery of 91.03% under the following optimum conditions: low ash high sulphur coal, Karanja oil, coal particle size of +75–200μm and pulp density of 3% (wt./vol.). The percentage contribution of each process parameter towards the agglomerate yield determined using Analysis of Variance (ANOVA) approach was found to be of the following order: coal particle size (55.35%)>type of coal (17.84%)>pulp density (16.50%)>type of oil (8.41%). The most influential process parameter appeared to be coal particle size which has been the primary criteria used for selection of particular process for coal washing. Linear regression analysis carried out using the SPSS 19.0 statistical software further supported the same. Further, a mathematical model was also developed to predict the agglomerate yield by oil agglomeration under the given set of boundary conditions. The experimentally obtained yields were in close agreement with the predicted yield of the model. The agglomerate yield (91.03%) obtained during the confirmation experiment carried out under optimum conditions was much higher than that observed in all the test runs and thereby, the authenticity of optimization was checked.

Critical oil–liquid interfacial tension for some oil-assisted fine particle processing methods

This paper presents that oil–liquid interfacial tension (γOL) value significantly affects the oil agglomeration and liquid–liquid extraction processes as oil-assisted methods in fine particle processing. The decrease in the oil–liquid interfacial tension leads to the decreases in the recoveries of minerals in both oil agglomeration and liquid–liquid extraction techniques. Eventually, these oil-assisted methods do not take place below a particular value of oil–liquid interfacial tension. The oil–liquid interfacial tension value at which oil agglomeration does not occur was defined as ‘critical oil–liquid interfacial tension for oil agglomeration, γc–OL–a’ and at which liquid–liquid extraction does not take place was also defined as ‘critical oil–liquid interfacial tension for liquid–liquid extraction, γc–OL–e’. Consequently, the oil–liquid interfacial tension of the medium for successful processes of oil agglomeration and liquid–liquid extraction of a mineral must be higher than the related critical interfacial tension value.

Study on Clean Coal Technology with Oil Agglomeration in Fujian Province

Abstract Based on the Fujian coal resource utilization and distribution, samples from Peifeng coal mining were chosen as research object. This paper studies the effects of deashing with oil agglomeration technology, which mainly includes of agglomeration size, coal concentration, oil types and its dosage, alcohol types and dosage, PAM types and dosage. The results showed that the ash content can be reduced from 32% to 2.8% by one time and the ash rejection rate is arrived to 93.0% when the slurry concentration is 11.1% and oil dosage is 12.5%.

No.28 石炭中の酸素含有率変化による油凝集選炭効率への影響評価(研究発表)

No.28 石炭中の酸素含有率変化による油凝集選炭効率への影響評価(研究発表)

Correlation of Flocculation and Agglomeration of Dolomite with its Wettability

Wettability is an important parameter which affects the shear flocculation and oil agglomeration behaviors of minerals. The critical surface tension of wetting (γc) as a wettability parameter describes wetting characteristics of any mineral. In this study, the correlation of shear flocculation and oil agglomeration processes of dolomite with its wettability parameter is investigated. The experimental studies have indicated that these processes improved with decreasing wettability depending on the increase of oleate adsorption despite a simultaneous increase in the zeta potential of dolomite. On the other hand, the flocculation and agglomeration of dolomite decreased with decreasing surface tension and did not occur below a particular value of surface tension, corresponding to the critical surface tension of wetting (γc) and the critical solution surface tension (γc-a) values, respectively. Also, the γc-a values are slightly higher than the γc values, indicating that the agglomeration of the particles requires a lower wettability.

Relationship between properties of oil/water emulsion and agglomeration of carbonate minerals

In this study, a modification of oil agglomeration processes of dolomite and magnesite particles has been proposed. In this method the emulsion of kerosene with dodecylammonium hydrochloride (DDAHCl) was added to the minerals suspension. The experimental results have demonstrated that the agglomeration was governed by the properties of oil/water interface such as zeta potential and interfacial tension ( γ o/w). Addition of cationic surfactant to the emulsion changed the zeta potential value from negative to positive, which resulted in enhanced the adhesion of the oil droplets to negatively charged particles, according to the DLVO theory. The presence of cationic surfactant has an effect on the size of the agglomerate. At the high DDAHCl concentration (21 mg/g solid) the recovery and diameter of agglomerates slightly decreased, and finally a paste was formed. It results from decrease of the value of γ o/w leading to the formation of weaker liquid bridges between solid particles. This explanation was supported by AFM measurements of adhesion forces.

7-1-2 植物油凝集法による中国重慶産微粉状廃棄石炭からの有機炭素成分の回収実験(7-1 リサイクル,Session 7 環境対策・リサイクル,研究発表)

7-1-2 植物油凝集法による中国重慶産微粉状廃棄石炭からの有機炭素成分の回収実験(7-1 リサイクル,Session 7 環境対策・リサイクル,研究発表)

Multi-response optimization of oil agglomeration with multiple performance characteristics

In this paper, the multi-response optimization of grade and recovery simultaneously using Taguchi quality loss function has been done for Zonguldak/Turkey bituminous coal by oil agglomeration. The controllable factors selected in this investigation are solid content, amount of oil, agitation time and agitation rate. The percentage contribution of each controllable factor has been determined on the performance of oil agglomeration. The amount of oil has been found as the most effective factor and its contribution is 65.42% on multiple quality characteristics. The confirmation experiment has also been carried out according to the optimum conditions predicted. The grade and recovery have been increased up to 0.565% and 93.04%, respectively against the initial value of grade and recovery as 0.436% and 75.08%, respectively. The results show considerable improvement in both the quality characteristics such as grade and recovery with the multi-response optimization used, as compared the initial value of grade and recovery.

Flotation of Fine Gold Particles by the Assistance of Coal-Oil Agglomerates

This paper describes the use of coal-oil agglomerates in flotation to increase the gold recovery from an ore containing fine gold particles. The effects of operating parameters on gold flotation recovery such as oil type, particle size of agglomerating material, agglomerate/ore and oil/ore ratios were investigated. The studies showed that petroleum oils are more effective than vegetable oils in oil agglomeration of Kozlu coal and coal-oil assisted gold flotation. Gold recovery can be increased using a higher amount of agglomerates in the process; however, gold grade of the flotation concentrates is reduced significantly. The use of bridging oil at high concentrations in the agglomeration process provides high-grade gold concentrates, but lower recoveries. The utilization of coarser coal particles in the coal-oil agglomeration stage leads to higher selectivity and recovery values for gold particles.

Optimization of experimental conditions for recovery of coking coal fines by oil agglomeration technique

The significance of coking coal in the metallurgical sector as well as the meager coking coal reserves across the globe increase the necessity to recover coking coal fines from the fine coking coal slurries generated from coal preparation and utilization activities. Oil agglomeration studies were carried out by varying the experimental conditions for maximum recovery of coking coal fines i.e., yield of the agglomerates. The various operational parameters studied were oil dosage, agitation speed, agglomeration time and pulp density. By using Taguchi experimental design, oil dosage (20%), agitation speed (1100 rpm), agglomeration time (3 min) and pulp density (4.5%) were identified as the optimized conditions. A confirmation experiment has also been carried out at the optimized conditions. The percentage contribution of each parameter on agglomerate yield was analyzed by adopting analysis of variance (ANOVA) statistical method as well as multiple linear regression analysis. The order of influence of the parameters on the agglomerate yield is of the following order: pulp density > oil dosage > agitation speed > agglomeration time. A mathematical model was developed to fit the set of experimental conditions with the yield obtained at each test run and also at the optimized conditions. The experimentally obtained yield was compared with the predicted yield of the model and the results indicate a maximum error of 5% between the two. A maximum yield of 90.42% predicted at the optimized conditions appeared to be in close agreement with the experimental yield thus indicating the accuracy of the model in predicting the results.

Role of hydrophobicity and surface tension on shear flocculation and oil agglomeration of magnesite

This paper describes the role of hydrophobicity and surface tension on the shear flocculation and oil agglomeration of magnesite mineral. The experimental results have demonstrated that these processes were closely correlated with the particle hydrophobicity; however, they were not lowered by increasing the surface charge due to sodium oleate adsorption. Also, higher degrees of hydrophobicity were required to achieve the maximum aggregation in the oil agglomeration of magnesite fines in comparison to its shear flocculation. On the other hand, these aggregation processes decreased depending on the decrease in the contact angle with decreasing surface tension. Eventually the shear flocculation and oil agglomeration of fine particles in the suspension did not take place below a particular value of surface tension, corresponding the critical surface tension of wetting ( γ c) and the critical solution surface tension ( γ c-a) values, respectively.

Desulfurization and de-ashing of a mixture of subbituminous coal and gangue minerals by selective oil agglomeration

The aim of this study was to investigate desulfurization and de-ashing of a mixture of subbituminous coal and gangue minerals by the agglomeration method. For this purpose, experimental studies were conducted on a mixture containing subbituminous coal, pyrite, quartz and calcite. The effects of some parameters that markedly influence the effectiveness of selective oil agglomeration, such as solid concentration, pH, bridging liquid type and concentration, and depressant type and amount, were investigated. Agglomeration results showed that the usage of various depressants (Na{sub 2}SiO{sub 3}, FeCl3, corn starch, wheat starch) in the agglomeration medium has a positive effect on the reduction of ash and total sulfur content of agglomerates. It was found that an agglomerate product containing 3.03% total sulfur and 25.01% ash with a total sulfur reduction of 56.71% was obtained from a feed that contained 7% total sulfur and 43.58% ash when FeCl{sub 3} was used in the agglomeration medium.

Selective Oil Agglomeration of Lignite

In this study, desulfurization and deashing of Adıyaman-Gölbaşı lignite by the agglomeration method were studied. For this purpose, three groups of agglomeration experiments were made. The effects of solid concentration, bridging liquid type and dosage, pH, and screen size on the agglomeration after desliming were investigated in the first group of experiments. The effects of lake water and sea water (the Mediterranean Sea water, the Aegean Sea water, and the Black Sea water) on the agglomeration were investigated in the second group of experiments. The effects of different salts (NaCl, MgCl2, and FeCl3) on the agglomeration were investigated in the third group of experiments. Agglomeration results showed that the usage of sea waters and soda lake water in the agglomeration medium had a positive effect on the reduction of total sulfur content of agglomerates. In addition, the usage of NaCl, MgCl2, and FeCl3 in the agglomeration medium had a positive effect on the ash content reduction of the agglomerates.

Optimization of some parameters on agglomeration performance of Zonguldak bituminous coal by oil agglomeration

In this study, the optimization of some parameters on agglomeration performance of Zonguldak bituminous coal by oil agglomeration was discussed. A three-level Box–Behnken design combining with a response surface methodology (RSM) and quadratic programming (QP) were employed for modeling and optimization some operations parameters on oil agglomeration performance. The relationship between the responses, i.e., grade and recovery, and four process parameters, i.e., amount of oil, agitation time, agitation rate and solid content were presented as empirical model equations for both grade and recovery on oil agglomeration. The model equations were then optimized individually using the quadratic programming method to maximize both for grade and recovery within the experimental range studied. The optimum conditions were found to be 14.61% for amount of oil, 8.94 min for agitation time, 1554 rpm for agitation rate and 5% for solid content to achieve the maximum grade. The maximum model prediction of 0.650 grade at these optimum conditions is higher than any value obtained in the initial tests conducted. Similarly, the conditions for maximum recovery were found to be 20.60% for amount of oil, 5 min for agitation time, 1800 rpm for agitation rate and 19.48% for solid content with a prediction of 96.90% recovery, which is also higher than any other recovery obtained in the initial tests conducted.